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Network Working Group                     K. Kompella (Juniper Networks)
Internet Draft                            Y. Rekhter  (Juniper Networks)
Expiration Date: August 2002              A. Banerjee (Calient Networks)
                                          J. Drake    (Calient Networks)
                                          G. Bernstein (Ciena)
                                          D. Fedyk    (Nortel Networks)
                                          E. Mannie   (GTS Network)
                                          D. Saha     (Tellium)
                                          V. Sharma   (Metanoia, Inc.)

            IS-IS Extensions in Support of Generalized MPLS


                draft-ietf-isis-gmpls-extensions-08.txt


1. Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as ``work in progress.''

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.















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Internet Draft   draft-ietf-isis-gmpls-extensions-08.txt   February 2002


2. Abstract

   This document specifies encoding of extensions to the IS-IS routing
   protocol in support of Generalized Multi-Protocol Label Switching
   (GMPLS).  The description of the extensions is specified in [GMPLS-
   ROUTING].


3. Summary for Sub-IP Area


3.1. Summary

   This document specifies encoding of extensions to the IS-IS routing
   protocol in support of Generalized Multi-Protocol Label Switching
   (GMPLS).  The description of the extensions is specified in [GMPLS-
   ROUTING].


3.2. Where does it fit in the Picture of the Sub-IP Work

   This work fits squarely in either CCAMP or IS-IS boxes.


3.3. Why is it Targeted at this WG

   This draft is targeted at either the CCAMP or IS-IS WGs, because this
   draft specifies the extensions to the IS-IS routing protocols in
   support of GMPLS, because GMPLS is within the scope of CCAMP WG, and
   because IS-IS is within the scope of the IS-IS WG.


3.4. Justification

   The WG should consider this document as it specifies the extensions
   to the IS-IS routing protocols in support of GMPLS.















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4. Introduction

   This document specifies extensions to the IS-IS routing protocol in
   support of carrying link state information for Generalized Multi-
   Protocol Label Switching (GMPLS). The set of required enhancements to
   IS-IS are outlined in [GMPLS-ROUTING].



5. IS-IS Routing Enhancements

   In this section we define the enhancements to the TE properties of
   GMPLS TE links that can be announced in IS-IS TE LSAs.

   In this document, we enhance the sub-TLVs for the extended IS
   reachability TLV (see [ISIS-TE]) in support of GMPLS. Specifically,
   we add the following sub-TLVs:

      1. Link Local Identifier
      2. Remote Interface Identifier
      3. Link Protection Type
      4. Interface Switching Capability Descriptor

   This brings the list of sub-TLVs of the extended IS reachability TLV
   to:

      Sub-TLV Type      Length    Name
                 3           4    Administrative group (color)
                 4           4    Link Local Identifier
                 5           4    Link Remote Identifier
                 6    variable    IPv4 interface address
                 8    variable    IPv4 neighbor address
                 9           4    Maximum link bandwidth
                10           4    Reservable link bandwidth
                11          32    Unreserved bandwidth
                18           3    TE Default metric
                20           2    Link Protection Type
                21    variable    Interface Switching Capability Descriptor
           250-254           -    Reserved for cisco specific extensions
               255           -    Reserved for future expansion


   We further add one new TLV to the TE LSAs.

          TLV Type      Length    Name
         138 (TBD)    variable    Shared Risk Link Group

   Finally, we add one more TLV to the Hello PDUs.



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          TLV Type      Length    Name
          (TBD)           4       Link Identifier


5.1. Link Local Identifier

   A Link Local Interface Identifier is a sub-TLV of the extended IS
   reachability TLV with type 4, and length 4.


5.2. Link Remote Identifier

   A Link Remote Identifier is a sub-TLV of the extended IS reachability
   TLV with type 5, and length 4.


5.3. Link Protection Type

   The Link  Protection Type is is a sub-TLV (of type 20) of the
   extended IS reachability TLV, with length two octets, the first of
   which is a bit vector describing the protection capabilities of the
   link. They are:

      0x01  Extra Traffic

      0x02  Unprotected

      0x04  Shared

      0x08  Dedicated 1:1

      0x10  Dedicated 1+1

      0x20 Enhanced

      0x40 Reserved

      0x80 Reserved


5.4. Interface Switching Capability Descriptor

   The Interface Switching Capability Descriptor is a sub-TLV (of type
   21) of the extended IS reachability TLV. The length is the length of
   value field in octets. The format of the value field is as shown
   below:





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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Switching Cap |   Encoding    |           Reserved            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 0              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 1              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 2              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 3              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 4              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 5              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 6              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Max LSP Bandwidth at priority 7              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Switching Capability-specific information              |
      |                  (variable)                                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Switching Capability (Switching Cap) field contains one of the
   following values:


           1     Packet-Switch Capable-1 (PSC-1)
           2     Packet-Switch Capable-2 (PSC-2)
           3     Packet-Switch Capable-3 (PSC-3)
           4     Packet-Switch Capable-4 (PSC-4)
           51    Layer-2 Switch Capable  (L2SC)
           100   Time-Division-Multiplex Capable (TDM)
           150   Lambda-Switch Capable   (LSC)
           200   Fiber-Switch Capable    (FSC)


   The Encoding field contains one of the values specified in Section
   3.1.1 of [GMPLS-SIG].

   Maximum LSP Bandwidth is encoded as a list of eight 4 octet fields in
   the IEEE floating point format, with priority 0 first and priority 7
   last. The units are bytes (not bits!) per second.

   The content of the Switching Capability specific information field



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   depends on the value of the Switching Capability field.

   When the Switching Capability field is PSC-1, PSC-2, PSC-3, or PSC-4,
   the specific information includes Interface MTU and Minimum LSP
   Bandwidth. The Interface MTU is encoded as a 2 octets integer.  The
   Minimum LSP Bandwidth is is encoded in a 4 octets field in the IEEE
   floating point format. The units are bytes (not bits!) per second.

   When the Switching Capability field is L2SC, there is no specific
   information.

   When the Switching Capability field is TDM, the specific information
   includes Minimum LSP Bandwidth, and an indication whether the
   interface supports Standard or Arbitrary SONET/SDH. The Minimum LSP
   Bandwidth is encoded in a 4 octets field in the IEEE floating point
   format. The units are bytes (not bits!) per second. The indication
   whether the interface supports Standard or Arbitrary SONET/SDH is
   encoded as 1 octet. The value of this octet is 0 if the interface
   supports Standard SONET/SDH, and 1 if the interface supports
   Arbitrary SONET/SDH.

   When the Switching Capability field is LSC, there is no specific
   information.

   The Interface Switching Capability Descriptor sub-TLV may occur more
   than once within the extended IS reachability TLV  (this is needed to
   handle interfaces that support multiple switching capabilities).


5.5. Shared Risk Link Group TLV

   The proposed SRLG (of type 138 TBD) contains a new data structure
   consisting of:

       7 octets of System ID and Pseudonode Number
       1 octet Flag
       4 octets of IPv4 interface address or 4 octets of a Link Local
         Identifier
       4 octets of IPv4 neighbor address or 4 octets of a Link Remote
         Identifier

   and a list of SRLG values, where each element in the list has 4
   octets. The length of this TLV is 16 + 4 * (number of SRLG values).
   The Least Significant Bit of the Flag octet indicates whether the
   interface is numbered (set to 1), or unnumbered (set to 0). All other
   bits are reserved and should be set to 0.





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5.6. Link Identifier for Unnumbered Interfaces

   The Link Identifier TLV is carried as part of the Point-to-point ISIS
   Hello PDUs. The Type field of this TLV is TBD. The Length field of
   this TLV is set to 4. The Value field of this TLV contains 4 octets
   that encode the Identifier assigned to the link over which this PDU
   is to be transmitted by the LSR that transmits the PDU.


6. Implications on Graceful Restart

   The restarting node should follow the ISIS restart procedures [ISIS-
   RESTART], and the RSVP-TE restart procedures [GMPLS-RSVP].

   Once the restarting node re-establishes at least one ISIS adjacency,
   the node should originate its TE LSAs. These LSAs should be
   originated with 0 unreserved bandwidth  until the node is able to
   determine the amount of unreserved resources taking into account the
   resources reserved by the already established LSPs that have been
   preserved across the restart. Once the restarting node determines the
   amount of unreserved resources, taking into account the resources
   reserved by the already established LSPs that have been preserved
   across the restart, the node should advertise these resources in its
   TE LSAs.

   Neighbors of the restarting node should continue advertise the actual
   unreserved bandwidth on the TE links from the neighbors to that node.

   Regular graceful restart should not be aborted if a TE LSA or TE
   topology changes. TE graceful restart need not be aborted if a TE LSA
   or TE topology changes.



7. Security Considerations

   The extensions proposed in this document does not raise any new
   security concerns.













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Internet Draft   draft-ietf-isis-gmpls-extensions-08.txt   February 2002


8. Acknowledgements

   The authors would like to thank Suresh Katukam, Jonathan Lang and
   Quaizar Vohra for their comments on the draft.


9. References

   [ISIS-TE] Smit, H., Li, T., "IS-IS Extensions for Traffic
   Engineering",
       draft-ietf-isis-traffic-03.txt (work in progress)

   [GMPLS-SIG] Generalized MPLS Group, "Generalized MPLS - Signaling
   Functional
       Description", draft-ietf-mpls-generalized-signaling-04.txt (work
       in progress)

   [GMPLS-ROUTING] "Routing Extensions in Support of Generalized MPLS",
       draft-many-ccamp-gmpls-routing-01.txt (work in progress)

   [ISIS-RESTART] "Restart signaling for ISIS", draft-ietf-isis-
   restart-00.txt
       (work in progress)

   [GMPLS-RSVP] "Generalized MPLS Signaling - RSVP-TE Extensions",
       draft-ietf-mpls-generalized-rsvp-te-06.txt (work in progress)



10. Authors' Information


Kireeti Kompella
Juniper Networks, Inc.
1194 N. Mathilda Ave
Sunnyvale, CA 94089
Email: kireeti@juniper.net



Yakov Rekhter
Juniper Networks, Inc.
1194 N. Mathilda Ave
Sunnyvale, CA 94089
Email: yakov@juniper.net






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Ayan Banerjee
Calient Networks
5853 Rue Ferrari
San Jose, CA 95138
Phone: +1.408.972.3645
Email: abanerjee@calient.net

John Drake
Calient Networks
5853 Rue Ferrari
San Jose, CA 95138
Phone: (408) 972-3720
Email: jdrake@calient.net



Greg Bernstein
Ciena Corporation
10480 Ridgeview Court
Cupertino, CA 94014
Phone: (408) 366-4713
Email: greg@ciena.com



Don Fedyk
Nortel Networks Corp.
600 Technology Park Drive
Billerica, MA 01821
Phone: +1-978-288-4506
Email: dwfedyk@nortelnetworks.com



Eric Mannie
GTS Network Services
RDI Department, Core Network Technology Group
Terhulpsesteenweg, 6A
1560 Hoeilaart, Belgium
Phone: +32-2-658.56.52
E-mail: eric.mannie@gtsgroup.com









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Debanjan Saha
Tellium Optical Systems
2 Crescent Place
P.O. Box 901
Ocean Port, NJ 07757
Phone: (732) 923-4264
Email: dsaha@tellium.com


Vishal Sharma
Metanoia, Inc.
335 Elan Village Lane, Unit 203
San Jose, CA 95134-2539
Phone: +1 408-943-1794
Email: v.sharma@ieee.org



































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